In Malaysia, the scene opens with Yelena Belova carrying out a covert operation, destroying a secret laboratory on behalf of Valentina Allegra de Fontaine, played by an actress I do not have the link for. De Fontaine, in a desperate attempt to cover up her connections with the O.X.E. Group and their dangerous "Sentry" superhuman project, aims to eliminate any evidence that could implicate her involvement. As her political career faces threats of impeachment due to her covert dealings, she sends a team of operatives—including John Walker, Ava Starr, and Antonia Dreykov—to a secret O.X.E. facility. Their mission is treacherous: they are ordered to eliminate each other within the compound, turning the operation into a deadly trap.
During this chaos, [Ava Starr] ends up killing [Antonia Dreykov], and an enigmatic, amnesiac man named Bob—who was previously thought dead—awakens from a suspended animation pod in the room. It quickly becomes clear that these operatives were set up as part of a cover-up, with De Fontaine’s plan to incinerate the evidence and silence anyone who might reveal her misconduct. Recognizing their shared predicament, Yelena, John Walker, and Ava unite, working together to escape the deadly trap. As they come into physical contact with Bob, they experience fleeting visions of some of their most traumatic memories, emphasizing their emotional struggles and the deep scars they carry.
De Fontaine soon learns that the group has survived, and she discovers that Bob was a volunteer in the elusive Sentry trials, presumed dead but now very much alive. When she arrives at the site, Bob creates a dramatic diversion by drawing enemy fire, allowing the others—Yelena, Walker, and Ava—to slip away. Remarkably, Bob sustains no injuries from being shot; instead, he begins to uncontrollably ascend into the air, then crash-lands back at the former Avengers Tower, now renamed the Watchtower. De Fontaine plans to reveal Bob as a super-powered protector to the world, modeling him as a new kind of hero to boost her political image and prevent her impeachment.
Meanwhile, Alexei Shostakov, a father-figure and ally of Yelena, who had overheard some of the clandestine plans while working as a freelance chauffeur, comes to their rescue. He refers to her team as the "Thunderbolts", a nickname inspired by Yelena’s childhood soccer team, symbolizing their unity and resilience.
In the political arena, Congressman Bucky Barnes is alerted by De Fontaine's assistant, Mel, about the group's survival and Bob’s extraordinary abilities. Barnes swiftly captures the team, intending to have them testify during the impeachment hearings, which puts them in a perilous position. Concerned about Bob, Mel urges Barnes to be cautious, but Barnes takes the Thunderbolts to New York City to infiltrate the Watchtower and rescue Bob. Once there, they discover that De Fontaine has convinced Bob to embrace a heroic identity called "Sentry" and manipulate public opinion in her favor. Bob, demonstrating his immense power, easily overcomes the Thunderbolts, but he chooses not to attack them in obedience to his sense of morality and innocence, despite orders from De Fontaine to eliminate them.
This defiance infuriates De Fontaine, who sees Bob’s growing independence as a threat. Bob develops a god-like delusion of superiority, turning against De Fontaine, who attempts to regain control. In a critical moment, Mel uses a failsafe kill switch, which triggers the re-emergence of Bob’s darker side: the Void, a destructive alter ego that embodies his depression, insecurities, and inner demons. The Void begins to spread supernatural darkness across New York City, trapping its citizens in haunting visions of traumatic memories, plunging the city into chaos.
Realizing that the only way to save the city is from within Bob’s mind, Yelena bravely ventures into the darkness to reach his consciousness. Inside, she faces her haunted past as a former Black Widow agent, confronting her own traumas and regrets. She finds Bob hiding in a recreated childhood bedroom, where he had sought refuge from an abusive father. As the Thunderbolts—including Chin Ka-Lok, Timmy Hung Tin-Ming, and others—join in tackling his traumas, they confront his struggles with drug addiction, loss, and guilt.
Together, they reach a pivotal memory: the moment of the Sentry procedure at the Malaysia lab. The Void, which they find nearby, quickly overpowers them. Bob’s fight to regain control threatens to fully consume him, but the team’s unwavering belief in his goodness—affirmed by their heartfelt embrace—gives Bob the strength to overcome the darkness. Light begins to seep back into the city, and the victims trapped in traumatic visions are finally freed.
With the Void neutralized, the Thunderbolts prepare to confront Valentina de Fontaine. In a staged press conference, she manipulates the public by announcing the team as the "New Avengers", claiming credit for their heroic actions. However, as Yelena quietly whispers to de Fontaine, “we own you now,” it is clear the team has some control over her and her schemes.
The story concludes with a post-credits scene set fourteen months later, where the New Avengers and Bob discuss tensions with Sam Wilson, who now leads his own Avengers team and is suing them for trademark infringement. Simultaneously, they face a growing threat in outer space, contacted by an unknown extraterrestrial spacecraft bearing a large "4" emblem on its side, hinting at more challenges ahead.
This complex narrative weaves themes of redemption, inner demons, and the struggle for identity, showcasing how heroes are shaped by their past traumas and how unity and belief can help overcome even the darkest darkness.
